Elastic-fluid turbine



Oct. 25,1927. 1,646,861

H. T. HERR ELASTIC FLUID TURBINE 7 Filed March 6, 1925 2 Sheets-Sheet} ITNESS S I INVENTOR .ATTORNEY Oct. 25,1927. 1,646,861

H. T. HERR ELASTIC FLUID TURBINE Filed March 25 2 Sheets-Sheet HIHm'r INVENTOR A A wwm ATTORNEY Patented Oct. 25, 1927.

UNITED STATES FATENT OFFICE.

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ELASTIC-FLUID TURBINE.

Application filed March 6, 1925. Serial No. 13,658.

My invention relates to improvements in elastic fluid turbines, and it has for its object to provide apparatus of the character designated wherein fluid may be expanded directly from certain intermediary moving stages to the exhaust, thus diminishing the volume of fluid traversing the final stage and permitting the use of a smaller and more efticient final stage than has hitherto been possible except at considerable expense and complication.

Tn the accompanying drawing, Fig. 1 is a side view, partially in section and partially in elevation, illustrating a steam turbine of the axial-flow type, embodying one form of my invention; Fig. 2 is a sectional view of a pair of blades used in the turbine of Fig. 1; Fig. 3 is a "fragmentary view similar to a portion of Fig. 1 and illustrating a modified form of final movingbladeyFig. l is a side view, partially in section and partially in elevation, showing the application of my invention to a turbine of the double rotation radial-flow type; and Fig. 5 is a back view of one of the rotors of Fig. 4, illustrating the method of carrying the final blade row on a spider.

In the construction and operation of steam turbines, particularly when operating with high vacuum, it has been a diificult problem to efliciently 'eitect the final expansion of the steam because of the relatively enormous volume thereoi' at modern condenser pressures. An undue blade length in the final rows isnot permissible because of the high tip speeds involved and, in order to secure adequate leaving area, it has been necessary to employ a relatively large leaving angle with consequent poor efilciency. V

In U. S. Reissue Patent No. 15,092, granted to the lVestinghouse Electric and Manufacturing Company on April 26, 1921 on an application filed by Karl Bauinann, a structure is described and claimed whereby the above defects are in a sense obviated. The steam is split into two or more annular streams or zones, and these zones are expanded at different rates, thus permitting the provision of an extremely large leaving area.

However. it has been found in the commercial construction of turbines of the Baumann type that, under certain conditions, the

decks or baiiies employed to split the steam stream into Zones set up more or less undesirable eddies with consequent inability to secure the steam flow therethrough which was contemplated in the design;

In accordance with the present invention, as carried out in a turbine of the axial-flow type, I expand the steam in the usual manner until the last stages are reached, and I then lnsert one or more rows of relatively wide, substantially fiat, blades having backwardly hooked tips disposed in operative relation to the exhaust space. The lateral edges of said wide blades are also curved so that a portion of the steam passes directly thereacross to succeeding stages and is expanded in the usual manner, whereas the remainder of the steam is completely expanded under said hooked tips and escapes to the exhaust space. Thus, the volume of steam to be handled in the final stages is materially diminished with the consequent possibility of securing extremely high eiiiciency in the last stages with an appreciable gain in the overall efiiciency of the turbine.

Referring to the drawing for a more us tailed understanding of my invention, I show a turbine casing at 10 in Fig. 1, this casing enclosing a spindle 11 operating in suitable bearings 12 and 18. The turbine is provided with the usual admission nozzle 14 and steam is first expanded through impulse stages indicated at 15. The steam then flows through blading 16 of any desired type, finally passing a fixed row of blading 17 and being discharged into a moving row of blades 18 of a form similar to that shown in U. S. Patent No. 1,469,965 issued to the Westin,'g fhouse Electric and Manufacturing Company October 9, 1923 on an application filed by Henry F. Schmidt. Briefly speaking, the blades 18 are relatively wide as compared with their height and, as shown more specifically in Fig. 2, they are forwardly and then rearwardly bent at the tips reform a hook portion 19, adjacent portions l9"19 together forming a throat 20 adapted to efficiently expand steam. The blades 18' are furthermore curved at the edges asindicated in section at 21 in Fig. 1 so as to receive and discharge steam in an axial direction, as is welllmown in the art.

The casing 10 embodies an exhaust chamber 22 in direct communication with an exhaust pipe 23, and the casing 10 further ems Steam leaving the lateral edge of the blades-25 passes through final blade rows 28 and 29 to the main exhaust chamber 22.

In order to suitably support the fixed blading 26 and 28 at the bottom of the turbine and to, at the same time, permit free flow of steam from the spaces 24 and 27 to the exhaust 23, I mount blades 26 and 28 on grid bars or beams 30 and 31, respectively.

The operation of the device will be obvious from the foregoing descriptlon. Steam expands in the usual manner through the blade row 17 and is delivered to the blade row 18, at which point its volume has attained such magnitude that it is desirableto reduce the same. A portion of the steam within the blade row 18 escapes through the throat 20 to exhaust, the size and proportlon of the throat 20 being such as to most efficiently expand the steam from the pressure obtained in the row 18 to exhaust pressure.

The residue of steam traversing the blade row '18 is reversed in the blade row 26 and suppliedto the blade rowi25 where still another, portion thereof is. completely expanded through the blade tlps and passes off through the exhaust, it being obviousthat a slightly different throat configuration is necessary at the tips of the blades 25 than at the tips of the blades 18 in order to efiiciently expand steam from a lower initial pressure to the same exhaust pressure. I

The residual steam escaping from the lateral edge of the blades 25 is completely expanded through theblade rows '28 and 29 and passestothe exhaust in the usual manner.

Referring to the form of my invention shown in Fig. 3, similar parts are numbered the same as in 'Fig. 1: but the last row of 7 moving lades, instead of being of the usual type indicated at 29 in Fig. 1, is of the clam shell or shovel type as shown at 29; that is to say, these blades are of relatively great width as compared with their height and they are further adapted to expand steam qefficiently over .the entire tip and leaving further shown in U. S. Patent No. 1,469,925

edge thereof, thus giving an enormous leaving area as clearly shown n Fig. 2 of the ELIEOIQIIIBIICIOHQCl Patent No. 1,469,965, or as issued to the Westinghouse Electric and Manufacturing Company on October 9, 1923 on an application filed by Alexander 'l'. Kasley.

Obviously my invention is not limited in i its application to turbines of the axial-flow type but may also be applied to turbines of the radial-flow type with single rotation or double rotation. A turbine of the latter type is indicated in Fig. 4, having wheels 40 and 41 mounted on shafts 42 and 43, respectively, for opposite rotation, these wheels being placed within a casing 44 and having interleaving blading 45, all as is well-known and space 47 as will be readily understood.

Similarly the wheel 40 carries a row of blades 48 having hooked tips, steam escaping therefrom through a spider 49 formed on the wheel 41. Fig.5 is a back view of the wheel 41, clearlyindicating the spider 4949 whereby steam is permitted to escape from the tips of the blades 48-48.

The final row of blading is shown at 50, being carried by the spider 49 49, and is of the general type. illustrated and claimed in U. S. Patent No. 1,488,117 issued to the lVestinghouse Electric and Manufacturing Company on March 25, 1924' on an application filed by the applicant, the blade being of a general semi-circularplan, with the exhaust edge running entirely around the curved periphery thereof. a

While I have shown my lnvention in sev eral forms, it will be obvious .to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the priorfart or as are specifically set forth in the appended claims.

.1 What I claim is 1. A multi-stage elastic fluid turbine 'provided with an exhaust chamber, the moving blades of'an intermediate. stage thereof having an inlet edge, a leaving edge curved in the form of reactionblading and exposed directly to the exhaust chamber, whereby a 'portionof the fluid supplied to said blades is completely expanded to exhaust pressure,

and a leaving edge disposed adjacent to a succeeding stage, curved in the form of re action blading, and adapted to partially expand the fluid passing thereover and to supply said fiuid to said succeedingstage.

2. A turbine as defined in claim 1 wherein therow of blading preceding the. said moving blades provides undivided passages between adjacent blades.v

3. A turbine as defined in elaim l wherein the said moving blades of the intermediate stage provide undivided passages between adjacent blades.

4. A turbine as defined in claim 1 wherein the blades of the said preceding and intermediate stages provide undivided passages between adjacent blades.

5. A multistage elastic fluid turbine of the axial flow type provided with an ex- I haust chamber, an intermediate moving stage thereof embodying substantially flat blades of relatively great width as compared With their length, the tips of said blades being curved backwardly in the form of reaction blading and being exposed directly to said exhaust chamber, whereby a portion of the fluid supplied to said blades is completely expanded to exhaust pressure at a small angle, the lateral leaving edge of said blades also being curved to partially expand the fluid passingthereover and to supply said fluid to a succeeding stage.

6. A multi-stage elastic fluid turbine provided with an exhaust chamber, the blades of a moving intermediate row thereof having inlet edges adjacent to the preceding row of blades, leaving edges adjacent to the succeeding row, and leaving edges exposed directly to said exhaustchamber formed to provide intervening nozzle passages adapted to expand elastic fluid to exhaust pressure, the adjacent blades in said intermediate row providing an undivided passage.

7. A multi-stage elastic fluid turbine provided with an exhaust chamber, the blades of a moving intermediate row thereof having inlet edges adjacent to the preceding row of blades, leaving edges adjacent to the succeeding row, and leaving edges exposed directly to said exhaust chamber formed to provide intervening nozzle passages adapted to expand elastic fluid to exhaust pressure, the adjacent blades in said preceding row providing an undivided passage.

8. A multi-st-age elastic fluid turbine provided with an exhaust chamber, the blades of a moving intermediate row thereof having inlet edges adjacent to the preceding row of blades, leaving edges adjacent to the succeeding row, and leaving edges exposed directly to said exhaust chamber formed to provide intervening nozzle passages adapted to expand elastic fluid to exhaust pressure, the adjacent blades in said preceding and in said intermediate row providing an undivided passage.

In testimony whereof, I have hereunto subscribed my name this eleventh day of February, 1925.

HERBERT T. HERB. 

